Where has consistent=y gone when using Datapump export

Posted by John Hallas on December 5, 2008

Well it is not needed anymore according to Oracle. Let’s take a look at a bit of history. From 9i, when flashback database came in, it was possible to export using a SCN number by setting the parameter flashback_scn or flashback_time. Below you can see the relevant options from a 10g exp help=y command

CONSISTENT cross-table consistency(N)

FLASHBACK_SCNSCN used to set session snapshot back to

FLASHBACK_TIMEtime used to get the SCN closest to the specified time

So both consistent=y and flashback options were available (provided you were using undo management).

Roll forward to 10g and onwards (and bear in mind that exp/imp are rumoured to be unsupported with 11g R2) and it appears obvious that using flashback is the way to go to get a consistent query/export using Datapump

Stephen Woodsaid

With using the FLASHBACK_TIME parameter in expdp it’s worth noting that you can’t create a ‘before change’ export if the table definition have changed e.g you added a column otherwise you’ll see this in the export log.